The kinetics of the H2 oxidation reaction at Nafion film covered Pt-black rotating disk electrodes (RDEs) in 0.5 M H2SO4 at 298 K was investigated by varying the Pt loading, Nafion film thickness, and rotating rate. The equation describing the H2 oxidation kinetics at an RDE with a NAfion film covered porous Pt layer was derived, assuming a Tafel-Volmer mechanism and taking into account the mass transfer resistances in the aqueous electrolyte, Nafion film, and Pt layer. The H2 oxidation reaction at the Pt layer was proved to be reversible and the measurable current density was determined entirely by the mass transfer of H2 in the aqueous electrolyte and the NAfion film; the apparent kinetic current density measured was due to the experimental error. More accurate results of kinetic analysis were obtained in this work than our results reported previously. (c) 2008 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.